Aluminum oxide molar mass

From the formula, the number of aluminum atoms is two and the number of oxygen atoms is three. Using the periodic table, a student can find the atomic masses of aluminum as grams per mole and oxygen as 16.9994 grams per mole. Multiplying the number of atoms of each of these elements by its respective atomic weight and then adding them, the molecular weight of Al2O3 is 101.961276 grams per mole.

The next step is to divide the molar mass of aluminum in the formula by the molar mass of Al2O3, or (2 x )/101.961276. This gives the result 0.5292507. To find the percentage of aluminum, multiply 0.5292507 by 100 percent to get 52.93 percent when rounded to the hundredth place.